title: Lesion of serotonergic neurons antagonizes clonidine induced suppression of avoidance behavior and locomotor activity in rats.
abstract: The effects of clonidine on avoidance acquisition and locomotor activity were studied in male Wistar rats with 5,6-dihydroxytryptamine (5,6-DHT) lesions of the median raphe nucleus. Lesioned animals showed marked depletion in forebrain serotonin and 5-hydroxyindole acetic acid concentrations. clonidine (0.2 mg/kg IP in a single daily dose for 6 consecutive days) inhibited avoidance acquisition and reduced locomotor activity in unlesioned rats. In 5,6-DHT rats clonidine failed to produce depressive effect. The resistance of raphe-lesioned rats to clonidine is discussed on the basis of possible interaction between noradrenergic and serotonergic brain systems.
mesh_terms: D015115:5,6-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000502:physiology*
chemical_list: D012701:Serotonin; D003000:Clonidine; D015115:5,6-Dihydroxytryptamine